Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=7a7d9a89d0307b1743d782197e2c5fc5ddf183f3
Commit:     7a7d9a89d0307b1743d782197e2c5fc5ddf183f3
Parent:     7c596fa964806acb3b5ababb7ec4e1da35b140b3
Author:     Mauro Carvalho Chehab <[EMAIL PROTECTED]>
AuthorDate: Thu Aug 23 16:26:14 2007 -0300
Committer:  Mauro Carvalho Chehab <[EMAIL PROTECTED]>
CommitDate: Tue Oct 9 22:14:55 2007 -0300

    V4L/DVB (6251): Replace video-buf to a more generic approach
    
    video-buf currently does two different tasks:
    
    - Manages video buffers with a common code that allows
      implementing all the V4L2 different modes of buffering;
    
    - Controls memory allocations
    
    While the first task is generic, the second were written to support PCI DMA
    Scatter/Gather needs. The original approach can't even work for those
    video capture hardware that don't support scatter/gather.
    
    I did one approach to make it more generic. While the approach worked
    fine for vivi driver, it were not generic enough to handle USB needs.
    
    This patch creates two different modules, one containing the generic
    video buffer handling (videobuf-core) and another with PCI DMA S/G.
    After this patch, it would be simpler to write an USB video-buf and a
    non-SG DMA module.
    
    Signed-off-by: Mauro Carvalho Chehab <[EMAIL PROTECTED]>
    http://thread.gmane.org/gmane.comp.video.video4linux/34978/focus=34981
    Reviewed-by: Ricardo Cerqueira <[EMAIL PROTECTED]>
---
 drivers/media/video/videobuf-core.c   |  976 +++++++++++++++++++++++++++++++++
 drivers/media/video/videobuf-dma-sg.c |  772 ++++++++++++++++++++++++++
 include/media/videobuf-core.h         |  236 ++++++++
 include/media/videobuf-dma-sg.h       |  142 +++++
 4 files changed, 2126 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf-core.c 
b/drivers/media/video/videobuf-core.c
new file mode 100644
index 0000000..2565013
--- /dev/null
+++ b/drivers/media/video/videobuf-core.c
@@ -0,0 +1,976 @@
+/*
+ * generic helper functions for handling video4linux capture buffers
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <[EMAIL PROTECTED]>
+ * (c) 2006 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <media/videobuf-core.h>
+
+#define MAGIC_BUFFER 0x20070728
+#define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \
+       { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); 
BUG(); }
+
+static int debug = 0;
+module_param(debug, int, 0644);
+
+MODULE_DESCRIPTION("helper module to manage video4linux buffers");
+MODULE_AUTHOR("Mauro Carvalho Chehab <[EMAIL PROTECTED]>");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, fmt, arg...)    if (debug >= level) \
+       printk(KERN_DEBUG "vbuf: " fmt , ## arg)
+
+/* --------------------------------------------------------------------- */
+
+#define CALL(q, f, arg...)                                             \
+       ( (q->int_ops->f)? q->int_ops->f(arg) : 0)
+
+void* videobuf_alloc(struct videobuf_queue* q)
+{
+       struct videobuf_buffer *vb;
+
+       BUG_ON (q->msize<sizeof(*vb));
+
+       if (!q->int_ops || !q->int_ops->alloc) {
+               printk(KERN_ERR "No specific ops defined!\n");
+               BUG();
+       }
+
+       vb = q->int_ops->alloc(q->msize);
+
+       if (NULL != vb) {
+               init_waitqueue_head(&vb->done);
+               vb->magic     = MAGIC_BUFFER;
+       }
+
+       return vb;
+}
+
+int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)
+{
+       int retval = 0;
+       DECLARE_WAITQUEUE(wait, current);
+
+       MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
+       add_wait_queue(&vb->done, &wait);
+       while (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED) {
+               if (non_blocking) {
+                       retval = -EAGAIN;
+                       break;
+               }
+               set_current_state(intr  ? TASK_INTERRUPTIBLE
+                                       : TASK_UNINTERRUPTIBLE);
+               if (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED)
+                       schedule();
+               set_current_state(TASK_RUNNING);
+               if (intr && signal_pending(current)) {
+                       dprintk(1,"buffer waiton: -EINTR\n");
+                       retval = -EINTR;
+                       break;
+               }
+       }
+       remove_wait_queue(&vb->done, &wait);
+       return retval;
+}
+
+int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
+                   struct v4l2_framebuffer *fbuf)
+{
+       MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       return CALL(q,iolock,q,vb,fbuf);
+}
+
+/* --------------------------------------------------------------------- */
+
+
+void videobuf_queue_init(struct videobuf_queue* q,
+                        struct videobuf_queue_ops *ops,
+                        void *dev,
+                        spinlock_t *irqlock,
+                        enum v4l2_buf_type type,
+                        enum v4l2_field field,
+                        unsigned int msize,
+                        void *priv)
+{
+       memset(q,0,sizeof(*q));
+       q->irqlock = irqlock;
+       q->dev     = dev;
+       q->type    = type;
+       q->field   = field;
+       q->msize   = msize;
+       q->ops     = ops;
+       q->priv_data = priv;
+
+       /* All buffer operations are mandatory */
+       BUG_ON (!q->ops->buf_setup);
+       BUG_ON (!q->ops->buf_prepare);
+       BUG_ON (!q->ops->buf_queue);
+       BUG_ON (!q->ops->buf_release);
+
+       mutex_init(&q->lock);
+       INIT_LIST_HEAD(&q->stream);
+}
+
+int videobuf_queue_is_busy(struct videobuf_queue *q)
+{
+       int i;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       if (q->streaming) {
+               dprintk(1,"busy: streaming active\n");
+               return 1;
+       }
+       if (q->reading) {
+               dprintk(1,"busy: pending read #1\n");
+               return 1;
+       }
+       if (q->read_buf) {
+               dprintk(1,"busy: pending read #2\n");
+               return 1;
+       }
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (NULL == q->bufs[i])
+                       continue;
+               if (CALL(q,is_mmapped,q->bufs[i])) {
+                       dprintk(1,"busy: buffer #%d mapped\n",i);
+                       return 1;
+               }
+               if (q->bufs[i]->state == STATE_QUEUED) {
+                       dprintk(1,"busy: buffer #%d queued\n",i);
+                       return 1;
+               }
+               if (q->bufs[i]->state == STATE_ACTIVE) {
+                       dprintk(1,"busy: buffer #%d avtive\n",i);
+                       return 1;
+               }
+       }
+       return 0;
+}
+
+void videobuf_queue_cancel(struct videobuf_queue *q)
+{
+       unsigned long flags=0;
+       int i;
+
+       /* remove queued buffers from list */
+       if (q->irqlock)
+               spin_lock_irqsave(q->irqlock,flags);
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (NULL == q->bufs[i])
+                       continue;
+               if (q->bufs[i]->state == STATE_QUEUED) {
+                       list_del(&q->bufs[i]->queue);
+                       q->bufs[i]->state = STATE_ERROR;
+               }
+       }
+       if (q->irqlock)
+               spin_unlock_irqrestore(q->irqlock,flags);
+
+       /* free all buffers + clear queue */
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (NULL == q->bufs[i])
+                       continue;
+               q->ops->buf_release(q,q->bufs[i]);
+       }
+       INIT_LIST_HEAD(&q->stream);
+}
+
+/* --------------------------------------------------------------------- */
+
+enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
+{
+       enum v4l2_field field = q->field;
+
+       BUG_ON(V4L2_FIELD_ANY == field);
+
+       if (V4L2_FIELD_ALTERNATE == field) {
+               if (V4L2_FIELD_TOP == q->last) {
+                       field   = V4L2_FIELD_BOTTOM;
+                       q->last = V4L2_FIELD_BOTTOM;
+               } else {
+                       field   = V4L2_FIELD_TOP;
+                       q->last = V4L2_FIELD_TOP;
+               }
+       }
+       return field;
+}
+
+static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
+                           struct videobuf_buffer *vb, enum v4l2_buf_type type)
+{
+       MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       b->index    = vb->i;
+       b->type     = type;
+
+       b->memory   = vb->memory;
+       switch (b->memory) {
+       case V4L2_MEMORY_MMAP:
+               b->m.offset  = vb->boff;
+               b->length    = vb->bsize;
+               break;
+       case V4L2_MEMORY_USERPTR:
+               b->m.userptr = vb->baddr;
+               b->length    = vb->bsize;
+               break;
+       case V4L2_MEMORY_OVERLAY:
+               b->m.offset  = vb->boff;
+               break;
+       }
+
+       b->flags    = 0;
+       if (CALL(q,is_mmapped,vb))
+               b->flags |= V4L2_BUF_FLAG_MAPPED;
+
+       switch (vb->state) {
+       case STATE_PREPARED:
+       case STATE_QUEUED:
+       case STATE_ACTIVE:
+               b->flags |= V4L2_BUF_FLAG_QUEUED;
+               break;
+       case STATE_DONE:
+       case STATE_ERROR:
+               b->flags |= V4L2_BUF_FLAG_DONE;
+               break;
+       case STATE_NEEDS_INIT:
+       case STATE_IDLE:
+               /* nothing */
+               break;
+       }
+
+       if (vb->input != UNSET) {
+               b->flags |= V4L2_BUF_FLAG_INPUT;
+               b->input  = vb->input;
+       }
+
+       b->field     = vb->field;
+       b->timestamp = vb->ts;
+       b->bytesused = vb->size;
+       b->sequence  = vb->field_count >> 1;
+}
+
+int videobuf_reqbufs(struct videobuf_queue *q,
+                struct v4l2_requestbuffers *req)
+{
+       unsigned int size,count;
+       int retval;
+
+       if (req->type != q->type) {
+               dprintk(1,"reqbufs: queue type invalid\n");
+               return -EINVAL;
+       }
+       if (req->count < 1) {
+               dprintk(1,"reqbufs: count invalid (%d)\n",req->count);
+               return -EINVAL;
+       }
+       if (req->memory != V4L2_MEMORY_MMAP     &&
+           req->memory != V4L2_MEMORY_USERPTR  &&
+           req->memory != V4L2_MEMORY_OVERLAY) {
+               dprintk(1,"reqbufs: memory type invalid\n");
+               return -EINVAL;
+       }
+
+       if (q->streaming) {
+               dprintk(1,"reqbufs: streaming already exists\n");
+               return -EBUSY;
+       }
+       if (!list_empty(&q->stream)) {
+               dprintk(1,"reqbufs: stream running\n");
+               return -EBUSY;
+       }
+
+       mutex_lock(&q->lock);
+       count = req->count;
+       if (count > VIDEO_MAX_FRAME)
+               count = VIDEO_MAX_FRAME;
+       size = 0;
+       q->ops->buf_setup(q,&count,&size);
+       size = PAGE_ALIGN(size);
+       dprintk(1,"reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
+               count, size, (count*size)>>PAGE_SHIFT);
+
+       retval = videobuf_mmap_setup(q,count,size,req->memory);
+       if (retval < 0) {
+               dprintk(1,"reqbufs: mmap setup returned %d\n",retval);
+               goto done;
+       }
+
+       req->count = count;
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
+{
+       if (unlikely(b->type != q->type)) {
+               dprintk(1,"querybuf: Wrong type.\n");
+               return -EINVAL;
+       }
+       if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
+               dprintk(1,"querybuf: index out of range.\n");
+               return -EINVAL;
+       }
+       if (unlikely(NULL == q->bufs[b->index])) {
+               dprintk(1,"querybuf: buffer is null.\n");
+               return -EINVAL;
+       }
+       videobuf_status(q,b,q->bufs[b->index],q->type);
+       return 0;
+}
+
+int videobuf_qbuf(struct videobuf_queue *q,
+             struct v4l2_buffer *b)
+{
+       struct videobuf_buffer *buf;
+       enum v4l2_field field;
+       unsigned long flags=0;
+       int retval;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       mutex_lock(&q->lock);
+       retval = -EBUSY;
+       if (q->reading) {
+               dprintk(1,"qbuf: Reading running...\n");
+               goto done;
+       }
+       retval = -EINVAL;
+       if (b->type != q->type) {
+               dprintk(1,"qbuf: Wrong type.\n");
+               goto done;
+       }
+       if (b->index < 0 || b->index >= VIDEO_MAX_FRAME) {
+               dprintk(1,"qbuf: index out of range.\n");
+               goto done;
+       }
+       buf = q->bufs[b->index];
+       if (NULL == buf) {
+               dprintk(1,"qbuf: buffer is null.\n");
+               goto done;
+       }
+       MAGIC_CHECK(buf->magic,MAGIC_BUFFER);
+       if (buf->memory != b->memory) {
+               dprintk(1,"qbuf: memory type is wrong.\n");
+               goto done;
+       }
+       if (buf->state != STATE_NEEDS_INIT && buf->state != STATE_IDLE) {
+               dprintk(1,"qbuf: buffer is already queued or active.\n");
+               goto done;
+       }
+
+       if (b->flags & V4L2_BUF_FLAG_INPUT) {
+               if (b->input >= q->inputs) {
+                       dprintk(1,"qbuf: wrong input.\n");
+                       goto done;
+               }
+               buf->input = b->input;
+       } else {
+               buf->input = UNSET;
+       }
+
+       switch (b->memory) {
+       case V4L2_MEMORY_MMAP:
+               if (0 == buf->baddr) {
+                       dprintk(1,"qbuf: mmap requested but buffer addr is 
zero!\n");
+                       goto done;
+               }
+               break;
+       case V4L2_MEMORY_USERPTR:
+               if (b->length < buf->bsize) {
+                       dprintk(1,"qbuf: buffer length is not enough\n");
+                       goto done;
+               }
+               if (STATE_NEEDS_INIT != buf->state && buf->baddr != 
b->m.userptr)
+                       q->ops->buf_release(q,buf);
+               buf->baddr = b->m.userptr;
+               break;
+       case V4L2_MEMORY_OVERLAY:
+               buf->boff = b->m.offset;
+               break;
+       default:
+               dprintk(1,"qbuf: wrong memory type\n");
+               goto done;
+       }
+
+       dprintk(1,"qbuf: requesting next field\n");
+       field = videobuf_next_field(q);
+       retval = q->ops->buf_prepare(q,buf,field);
+       if (0 != retval) {
+               dprintk(1,"qbuf: buffer_prepare returned %d\n",retval);
+               goto done;
+       }
+
+       list_add_tail(&buf->stream,&q->stream);
+       if (q->streaming) {
+               if (q->irqlock)
+                       spin_lock_irqsave(q->irqlock,flags);
+               q->ops->buf_queue(q,buf);
+               if (q->irqlock)
+                       spin_unlock_irqrestore(q->irqlock,flags);
+       }
+       dprintk(1,"qbuf: succeded\n");
+       retval = 0;
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+int videobuf_dqbuf(struct videobuf_queue *q,
+              struct v4l2_buffer *b, int nonblocking)
+{
+       struct videobuf_buffer *buf;
+       int retval;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       mutex_lock(&q->lock);
+       retval = -EBUSY;
+       if (q->reading) {
+               dprintk(1,"dqbuf: Reading running...\n");
+               goto done;
+       }
+       retval = -EINVAL;
+       if (b->type != q->type) {
+               dprintk(1,"dqbuf: Wrong type.\n");
+               goto done;
+       }
+       if (list_empty(&q->stream)) {
+               dprintk(1,"dqbuf: stream running\n");
+               goto done;
+       }
+       buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
+       retval = videobuf_waiton(buf, nonblocking, 1);
+       if (retval < 0) {
+               dprintk(1,"dqbuf: waiton returned %d\n",retval);
+               goto done;
+       }
+       switch (buf->state) {
+       case STATE_ERROR:
+               dprintk(1,"dqbuf: state is error\n");
+               retval = -EIO;
+               CALL(q,sync,q, buf);
+               buf->state = STATE_IDLE;
+               break;
+       case STATE_DONE:
+               dprintk(1,"dqbuf: state is done\n");
+               CALL(q,sync,q, buf);
+               buf->state = STATE_IDLE;
+               break;
+       default:
+               dprintk(1,"dqbuf: state invalid\n");
+               retval = -EINVAL;
+               goto done;
+       }
+       list_del(&buf->stream);
+       memset(b,0,sizeof(*b));
+       videobuf_status(q,b,buf,q->type);
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+int videobuf_streamon(struct videobuf_queue *q)
+{
+       struct videobuf_buffer *buf;
+       struct list_head *list;
+       unsigned long flags=0;
+       int retval;
+
+       mutex_lock(&q->lock);
+       retval = -EBUSY;
+       if (q->reading)
+               goto done;
+       retval = 0;
+       if (q->streaming)
+               goto done;
+       q->streaming = 1;
+       if (q->irqlock)
+               spin_lock_irqsave(q->irqlock,flags);
+       list_for_each(list,&q->stream) {
+               buf = list_entry(list, struct videobuf_buffer, stream);
+               if (buf->state == STATE_PREPARED)
+                       q->ops->buf_queue(q,buf);
+       }
+       if (q->irqlock)
+               spin_unlock_irqrestore(q->irqlock,flags);
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+int videobuf_streamoff(struct videobuf_queue *q)
+{
+       int retval = -EINVAL;
+
+       mutex_lock(&q->lock);
+       if (!q->streaming)
+               goto done;
+       videobuf_queue_cancel(q);
+       q->streaming = 0;
+       retval = 0;
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
+                                     char __user *data,
+                                     size_t count, loff_t *ppos)
+{
+       enum v4l2_field field;
+       unsigned long flags=0;
+       int retval;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       /* setup stuff */
+       q->read_buf = videobuf_alloc(q);
+       if (NULL == q->read_buf)
+               return -ENOMEM;
+
+       q->read_buf->memory = V4L2_MEMORY_USERPTR;
+       q->read_buf->baddr  = (unsigned long)data;
+       q->read_buf->bsize  = count;
+
+       field = videobuf_next_field(q);
+       retval = q->ops->buf_prepare(q,q->read_buf,field);
+       if (0 != retval)
+               goto done;
+
+       /* start capture & wait */
+       if (q->irqlock)
+               spin_lock_irqsave(q->irqlock,flags);
+       q->ops->buf_queue(q,q->read_buf);
+       if (q->irqlock)
+               spin_unlock_irqrestore(q->irqlock,flags);
+       retval = videobuf_waiton(q->read_buf,0,0);
+       if (0 == retval) {
+               CALL(q,sync,q,q->read_buf);
+               if (STATE_ERROR == q->read_buf->state)
+                       retval = -EIO;
+               else
+                       retval = q->read_buf->size;
+       }
+
+ done:
+       /* cleanup */
+       q->ops->buf_release(q,q->read_buf);
+       kfree(q->read_buf);
+       q->read_buf = NULL;
+       return retval;
+}
+
+ssize_t videobuf_read_one(struct videobuf_queue *q,
+                         char __user *data, size_t count, loff_t *ppos,
+                         int nonblocking)
+{
+       enum v4l2_field field;
+       unsigned long flags=0;
+       unsigned size, nbufs;
+       int retval;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       mutex_lock(&q->lock);
+
+       nbufs = 1; size = 0;
+       q->ops->buf_setup(q,&nbufs,&size);
+
+       if (NULL == q->read_buf  &&
+           count >= size        &&
+           !nonblocking) {
+               retval = videobuf_read_zerocopy(q,data,count,ppos);
+               if (retval >= 0  ||  retval == -EIO)
+                       /* ok, all done */
+                       goto done;
+               /* fallback to kernel bounce buffer on failures */
+       }
+
+       if (NULL == q->read_buf) {
+               /* need to capture a new frame */
+               retval = -ENOMEM;
+               q->read_buf = videobuf_alloc(q);
+
+               dprintk(1,"video alloc=0x%p\n", q->read_buf);
+               if (NULL == q->read_buf)
+                       goto done;
+               q->read_buf->memory = V4L2_MEMORY_USERPTR;
+               q->read_buf->bsize = count; /* preferred size */
+               field = videobuf_next_field(q);
+               retval = q->ops->buf_prepare(q,q->read_buf,field);
+
+               if (0 != retval) {
+                       kfree (q->read_buf);
+                       q->read_buf = NULL;
+                       goto done;
+               }
+               if (q->irqlock)
+                       spin_lock_irqsave(q->irqlock,flags);
+
+               q->ops->buf_queue(q,q->read_buf);
+               if (q->irqlock)
+                       spin_unlock_irqrestore(q->irqlock,flags);
+               q->read_off = 0;
+       }
+
+       /* wait until capture is done */
+       retval = videobuf_waiton(q->read_buf, nonblocking, 1);
+       if (0 != retval)
+               goto done;
+
+       CALL(q,sync,q,q->read_buf);
+
+       if (STATE_ERROR == q->read_buf->state) {
+               /* catch I/O errors */
+               q->ops->buf_release(q,q->read_buf);
+               kfree(q->read_buf);
+               q->read_buf = NULL;
+               retval = -EIO;
+               goto done;
+       }
+
+       /* Copy to userspace */
+       retval=CALL(q,copy_to_user,q,data,count,nonblocking);
+       if (retval<0)
+               goto done;
+
+       q->read_off += retval;
+       if (q->read_off == q->read_buf->size) {
+               /* all data copied, cleanup */
+               q->ops->buf_release(q,q->read_buf);
+               kfree(q->read_buf);
+               q->read_buf = NULL;
+       }
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+int videobuf_read_start(struct videobuf_queue *q)
+{
+       enum v4l2_field field;
+       unsigned long flags=0;
+       int count = 0, size = 0;
+       int err, i;
+
+       q->ops->buf_setup(q,&count,&size);
+       if (count < 2)
+               count = 2;
+       if (count > VIDEO_MAX_FRAME)
+               count = VIDEO_MAX_FRAME;
+       size = PAGE_ALIGN(size);
+
+       err = videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
+       if (err)
+               return err;
+
+       for (i = 0; i < count; i++) {
+               field = videobuf_next_field(q);
+               err = q->ops->buf_prepare(q,q->bufs[i],field);
+               if (err)
+                       return err;
+               list_add_tail(&q->bufs[i]->stream, &q->stream);
+       }
+       if (q->irqlock)
+               spin_lock_irqsave(q->irqlock,flags);
+       for (i = 0; i < count; i++)
+               q->ops->buf_queue(q,q->bufs[i]);
+       if (q->irqlock)
+               spin_unlock_irqrestore(q->irqlock,flags);
+       q->reading = 1;
+       return 0;
+}
+
+void videobuf_read_stop(struct videobuf_queue *q)
+{
+       int i;
+
+       videobuf_queue_cancel(q);
+       videobuf_mmap_free(q);
+       INIT_LIST_HEAD(&q->stream);
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (NULL == q->bufs[i])
+                       continue;
+               kfree(q->bufs[i]);
+               q->bufs[i] = NULL;
+       }
+       q->read_buf = NULL;
+       q->reading  = 0;
+}
+
+ssize_t videobuf_read_stream(struct videobuf_queue *q,
+                            char __user *data, size_t count, loff_t *ppos,
+                            int vbihack, int nonblocking)
+{
+       int rc, retval;
+       unsigned long flags=0;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       dprintk(2,"%s\n",__FUNCTION__);
+       mutex_lock(&q->lock);
+       retval = -EBUSY;
+       if (q->streaming)
+               goto done;
+       if (!q->reading) {
+               retval = videobuf_read_start(q);
+               if (retval < 0)
+                       goto done;
+       }
+
+       retval = 0;
+       while (count > 0) {
+               /* get / wait for data */
+               if (NULL == q->read_buf) {
+                       q->read_buf = list_entry(q->stream.next,
+                                                struct videobuf_buffer,
+                                                stream);
+                       list_del(&q->read_buf->stream);
+                       q->read_off = 0;
+               }
+               rc = videobuf_waiton(q->read_buf, nonblocking, 1);
+               if (rc < 0) {
+                       if (0 == retval)
+                               retval = rc;
+                       break;
+               }
+
+               if (q->read_buf->state == STATE_DONE) {
+                       rc = CALL (q,copy_stream, q, data, count,
+                                       retval, vbihack, nonblocking);
+                       if (rc < 0) {
+                               retval = rc;
+                               break;
+                       }
+                       retval      += rc;
+                       count       -= rc;
+                       q->read_off += rc;
+               } else {
+                       /* some error */
+                       q->read_off = q->read_buf->size;
+                       if (0 == retval)
+                               retval = -EIO;
+               }
+
+               /* requeue buffer when done with copying */
+               if (q->read_off == q->read_buf->size) {
+                       list_add_tail(&q->read_buf->stream,
+                                     &q->stream);
+                       if (q->irqlock)
+                               spin_lock_irqsave(q->irqlock,flags);
+                       q->ops->buf_queue(q,q->read_buf);
+                       if (q->irqlock)
+                               spin_unlock_irqrestore(q->irqlock,flags);
+                       q->read_buf = NULL;
+               }
+               if (retval < 0)
+                       break;
+       }
+
+ done:
+       mutex_unlock(&q->lock);
+       return retval;
+}
+
+unsigned int videobuf_poll_stream(struct file *file,
+                                 struct videobuf_queue *q,
+                                 poll_table *wait)
+{
+       struct videobuf_buffer *buf = NULL;
+       unsigned int rc = 0;
+
+       mutex_lock(&q->lock);
+       if (q->streaming) {
+               if (!list_empty(&q->stream))
+                       buf = list_entry(q->stream.next,
+                                        struct videobuf_buffer, stream);
+       } else {
+               if (!q->reading)
+                       videobuf_read_start(q);
+               if (!q->reading) {
+                       rc = POLLERR;
+               } else if (NULL == q->read_buf) {
+                       q->read_buf = list_entry(q->stream.next,
+                                                struct videobuf_buffer,
+                                                stream);
+                       list_del(&q->read_buf->stream);
+                       q->read_off = 0;
+               }
+               buf = q->read_buf;
+       }
+       if (!buf)
+               rc = POLLERR;
+
+       if (0 == rc) {
+               poll_wait(file, &buf->done, wait);
+               if (buf->state == STATE_DONE ||
+                   buf->state == STATE_ERROR)
+                       rc = POLLIN|POLLRDNORM;
+       }
+       mutex_unlock(&q->lock);
+       return rc;
+}
+
+int videobuf_mmap_setup(struct videobuf_queue *q,
+                       unsigned int bcount, unsigned int bsize,
+                       enum v4l2_memory memory)
+{
+       unsigned int i;
+       int err;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       err = videobuf_mmap_free(q);
+       if (0 != err)
+               return err;
+
+       /* Allocate and initialize buffers */
+       for (i = 0; i < bcount; i++) {
+               q->bufs[i] = videobuf_alloc(q);
+
+               q->bufs[i]->i      = i;
+               q->bufs[i]->input  = UNSET;
+               q->bufs[i]->memory = memory;
+               q->bufs[i]->bsize  = bsize;
+               switch (memory) {
+               case V4L2_MEMORY_MMAP:
+                       q->bufs[i]->boff  = bsize * i;
+                       break;
+               case V4L2_MEMORY_USERPTR:
+               case V4L2_MEMORY_OVERLAY:
+                       /* nothing */
+                       break;
+               }
+       }
+
+       dprintk(1,"mmap setup: %d buffers, %d bytes each\n",
+               bcount,bsize);
+
+       return 0;
+}
+
+int videobuf_mmap_free(struct videobuf_queue *q)
+{
+       int i;
+       int rc;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       rc  = CALL(q,mmap_free,q);
+       if (rc<0)
+               return rc;
+
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (NULL == q->bufs[i])
+                       continue;
+               q->ops->buf_release(q,q->bufs[i]);
+               kfree(q->bufs[i]);
+               q->bufs[i] = NULL;
+       }
+
+       return rc;
+}
+
+int videobuf_mmap_mapper(struct videobuf_queue *q,
+                        struct vm_area_struct *vma)
+{
+       int retval;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       mutex_lock(&q->lock);
+       retval=CALL(q,mmap_mapper,q,vma);
+       mutex_unlock(&q->lock);
+
+       return retval;
+}
+
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+int videobuf_cgmbuf(struct videobuf_queue *q,
+                   struct video_mbuf *mbuf, int count)
+{
+       struct v4l2_requestbuffers req;
+       int rc,i;
+
+       MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+       memset(&req,0,sizeof(req));
+       req.type   = q->type;
+       req.count  = count;
+       req.memory = V4L2_MEMORY_MMAP;
+       rc = videobuf_reqbufs(q,&req);
+       if (rc < 0)
+               return rc;
+
+       mbuf->frames = req.count;
+       mbuf->size   = 0;
+       for (i = 0; i < mbuf->frames; i++) {
+               mbuf->offsets[i]  = q->bufs[i]->boff;
+               mbuf->size       += q->bufs[i]->bsize;
+       }
+
+       return 0;
+}
+#endif
+
+/* --------------------------------------------------------------------- */
+
+EXPORT_SYMBOL_GPL(videobuf_waiton);
+EXPORT_SYMBOL_GPL(videobuf_iolock);
+
+EXPORT_SYMBOL_GPL(videobuf_alloc);
+
+EXPORT_SYMBOL_GPL(videobuf_queue_init);
+EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
+EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
+
+EXPORT_SYMBOL_GPL(videobuf_next_field);
+EXPORT_SYMBOL_GPL(videobuf_reqbufs);
+EXPORT_SYMBOL_GPL(videobuf_querybuf);
+EXPORT_SYMBOL_GPL(videobuf_qbuf);
+EXPORT_SYMBOL_GPL(videobuf_dqbuf);
+EXPORT_SYMBOL_GPL(videobuf_cgmbuf);
+EXPORT_SYMBOL_GPL(videobuf_streamon);
+EXPORT_SYMBOL_GPL(videobuf_streamoff);
+
+EXPORT_SYMBOL_GPL(videobuf_read_start);
+EXPORT_SYMBOL_GPL(videobuf_read_stop);
+EXPORT_SYMBOL_GPL(videobuf_read_stream);
+EXPORT_SYMBOL_GPL(videobuf_read_one);
+EXPORT_SYMBOL_GPL(videobuf_poll_stream);
+
+EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
+EXPORT_SYMBOL_GPL(videobuf_mmap_free);
+EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */
diff --git a/drivers/media/video/videobuf-dma-sg.c 
b/drivers/media/video/videobuf-dma-sg.c
new file mode 100644
index 0000000..3345877
--- /dev/null
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -0,0 +1,772 @@
+/*
+ * helper functions for PCI DMA video4linux capture buffers
+ *
+ * The functions expect the hardware being able to scatter gatter
+ * (i.e. the buffers are not linear in physical memory, but fragmented
+ * into PAGE_SIZE chunks).  They also assume the driver does not need
+ * to touch the video data.
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <[EMAIL PROTECTED]>
+ * (c) 2006 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <linux/pci.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#include <media/videobuf-dma-sg.h>
+
+#define MAGIC_DMABUF 0x19721112
+#define MAGIC_SG_MEM 0x17890714
+
+#define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \
+       { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); 
BUG(); }
+
+static int debug = 0;
+module_param(debug, int, 0644);
+
+MODULE_DESCRIPTION("helper module to manage video4linux pci dma sg buffers");
+MODULE_AUTHOR("Mauro Carvalho Chehab <[EMAIL PROTECTED]>");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, fmt, arg...)    if (debug >= level) \
+       printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
+
+/* --------------------------------------------------------------------- */
+
+struct scatterlist*
+videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages)
+{
+       struct scatterlist *sglist;
+       struct page *pg;
+       int i;
+
+       sglist = kcalloc(nr_pages, sizeof(struct scatterlist), GFP_KERNEL);
+       if (NULL == sglist)
+               return NULL;
+       for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
+               pg = vmalloc_to_page(virt);
+               if (NULL == pg)
+                       goto err;
+               BUG_ON(PageHighMem(pg));
+               sglist[i].page   = pg;
+               sglist[i].length = PAGE_SIZE;
+       }
+       return sglist;
+
+ err:
+       kfree(sglist);
+       return NULL;
+}
+
+struct scatterlist*
+videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
+{
+       struct scatterlist *sglist;
+       int i = 0;
+
+       if (NULL == pages[0])
+               return NULL;
+       sglist = kcalloc(nr_pages, sizeof(*sglist), GFP_KERNEL);
+       if (NULL == sglist)
+               return NULL;
+
+       if (NULL == pages[0])
+               goto nopage;
+       if (PageHighMem(pages[0]))
+               /* DMA to highmem pages might not work */
+               goto highmem;
+       sglist[0].page   = pages[0];
+       sglist[0].offset = offset;
+       sglist[0].length = PAGE_SIZE - offset;
+       for (i = 1; i < nr_pages; i++) {
+               if (NULL == pages[i])
+                       goto nopage;
+               if (PageHighMem(pages[i]))
+                       goto highmem;
+               sglist[i].page   = pages[i];
+               sglist[i].length = PAGE_SIZE;
+       }
+       return sglist;
+
+ nopage:
+       dprintk(2,"sgl: oops - no page\n");
+       kfree(sglist);
+       return NULL;
+
+ highmem:
+       dprintk(2,"sgl: oops - highmem page\n");
+       kfree(sglist);
+       return NULL;
+}
+
+/* --------------------------------------------------------------------- */
+
+struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf)
+{
+       struct videbuf_pci_sg_memory *mem=buf->priv;
+       BUG_ON (!mem);
+
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       return &mem->dma;
+}
+
+void videobuf_dma_init(struct videobuf_dmabuf *dma)
+{
+       memset(dma,0,sizeof(*dma));
+       dma->magic = MAGIC_DMABUF;
+}
+
+int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
+                          unsigned long data, unsigned long size)
+{
+       unsigned long first,last;
+       int err, rw = 0;
+
+       dma->direction = direction;
+       switch (dma->direction) {
+       case PCI_DMA_FROMDEVICE: rw = READ;  break;
+       case PCI_DMA_TODEVICE:   rw = WRITE; break;
+       default:                 BUG();
+       }
+
+       first = (data          & PAGE_MASK) >> PAGE_SHIFT;
+       last  = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
+       dma->offset   = data & ~PAGE_MASK;
+       dma->nr_pages = last-first+1;
+       dma->pages = kmalloc(dma->nr_pages * sizeof(struct page*),
+                            GFP_KERNEL);
+       if (NULL == dma->pages)
+               return -ENOMEM;
+       dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
+               data,size,dma->nr_pages);
+
+       dma->varea = (void *) data;
+
+       down_read(&current->mm->mmap_sem);
+       err = get_user_pages(current,current->mm,
+                            data & PAGE_MASK, dma->nr_pages,
+                            rw == READ, 1, /* force */
+                            dma->pages, NULL);
+       up_read(&current->mm->mmap_sem);
+       if (err != dma->nr_pages) {
+               dma->nr_pages = (err >= 0) ? err : 0;
+               dprintk(1,"get_user_pages: err=%d [%d]\n",err,dma->nr_pages);
+               return err < 0 ? err : -EINVAL;
+       }
+       return 0;
+}
+
+int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
+                            int nr_pages)
+{
+       dprintk(1,"init kernel [%d pages]\n",nr_pages);
+       dma->direction = direction;
+       dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
+       if (NULL == dma->vmalloc) {
+               dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages);
+               return -ENOMEM;
+       }
+       dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
+                               (unsigned long)dma->vmalloc,
+                               nr_pages << PAGE_SHIFT);
+       memset(dma->vmalloc,0,nr_pages << PAGE_SHIFT);
+       dma->nr_pages = nr_pages;
+       return 0;
+}
+
+int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
+                             dma_addr_t addr, int nr_pages)
+{
+       dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n",
+               nr_pages,(unsigned long)addr);
+       dma->direction = direction;
+       if (0 == addr)
+               return -EINVAL;
+
+       dma->bus_addr = addr;
+       dma->nr_pages = nr_pages;
+       return 0;
+}
+
+int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
+{
+       void                   *dev=q->dev;
+       struct videobuf_dma_sg_ops *ops=q->priv_ops;
+
+       MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
+       BUG_ON(0 == dma->nr_pages);
+
+       if (dma->pages) {
+               dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
+                                                  dma->offset);
+       }
+       if (dma->vmalloc) {
+               dma->sglist = videobuf_vmalloc_to_sg
+                                               (dma->vmalloc,dma->nr_pages);
+       }
+       if (dma->bus_addr) {
+               dma->sglist = kmalloc(sizeof(struct scatterlist), GFP_KERNEL);
+               if (NULL != dma->sglist) {
+                       dma->sglen  = 1;
+                       sg_dma_address(&dma->sglist[0]) = dma->bus_addr & 
PAGE_MASK;
+                       dma->sglist[0].offset           = dma->bus_addr & 
~PAGE_MASK;
+                       sg_dma_len(&dma->sglist[0])     = dma->nr_pages * 
PAGE_SIZE;
+               }
+       }
+       if (NULL == dma->sglist) {
+               dprintk(1,"scatterlist is NULL\n");
+               return -ENOMEM;
+       }
+       if (!dma->bus_addr) {
+               if (ops && ops->vb_map_sg) {
+                       dma->sglen = ops->vb_map_sg(dev,dma->sglist,
+                                       dma->nr_pages, dma->direction);
+               }
+               if (0 == dma->sglen) {
+                       printk(KERN_WARNING
+                              "%s: videobuf_map_sg failed\n",__FUNCTION__);
+                       kfree(dma->sglist);
+                       dma->sglist = NULL;
+                       dma->sglen = 0;
+                       return -EIO;
+               }
+       }
+       return 0;
+}
+
+int videobuf_dma_sync(struct videobuf_queue *q,struct videobuf_dmabuf *dma)
+{
+       void                   *dev=q->dev;
+       struct videobuf_dma_sg_ops *ops=q->priv_ops;
+
+       MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
+       BUG_ON(!dma->sglen);
+
+       if (!dma->bus_addr && ops && ops->vb_dma_sync_sg)
+               ops->vb_dma_sync_sg(dev,dma->sglist,dma->nr_pages,
+                                                       dma->direction);
+
+       return 0;
+}
+
+int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
+{
+       void                   *dev=q->dev;
+       struct videobuf_dma_sg_ops *ops=q->priv_ops;
+
+       MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
+       if (!dma->sglen)
+               return 0;
+
+       if (!dma->bus_addr && ops && ops->vb_unmap_sg)
+                       ops->vb_unmap_sg(dev,dma->sglist,dma->nr_pages,
+                                                       dma->direction);
+       kfree(dma->sglist);
+       dma->sglist = NULL;
+       dma->sglen = 0;
+       return 0;
+}
+
+int videobuf_dma_free(struct videobuf_dmabuf *dma)
+{
+       MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
+       BUG_ON(dma->sglen);
+
+       if (dma->pages) {
+               int i;
+               for (i=0; i < dma->nr_pages; i++)
+                       page_cache_release(dma->pages[i]);
+               kfree(dma->pages);
+               dma->pages = NULL;
+       }
+
+       vfree(dma->vmalloc);
+       dma->vmalloc = NULL;
+       dma->varea = NULL;
+
+       if (dma->bus_addr) {
+               dma->bus_addr = 0;
+       }
+       dma->direction = PCI_DMA_NONE;
+       return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma)
+{
+       struct videobuf_queue q;
+       struct videobuf_dma_sg_ops qops;
+
+       q.dev=pci;
+       qops.vb_map_sg=(vb_map_sg_t *)pci_map_sg;
+       qops.vb_unmap_sg=(vb_map_sg_t *)pci_unmap_sg;
+       q.priv_ops = &qops;
+
+       return (videobuf_dma_map(&q,dma));
+}
+
+int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma)
+{
+       struct videobuf_queue q;
+       struct videobuf_dma_sg_ops qops;
+
+       q.dev=pci;
+       qops.vb_map_sg=(vb_map_sg_t *)pci_map_sg;
+       qops.vb_unmap_sg=(vb_map_sg_t *)pci_unmap_sg;
+       q.priv_ops = &qops;
+
+       return (videobuf_dma_unmap(&q,dma));
+}
+
+/* --------------------------------------------------------------------- */
+
+static void
+videobuf_vm_open(struct vm_area_struct *vma)
+{
+       struct videobuf_mapping *map = vma->vm_private_data;
+
+       dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map,
+               map->count,vma->vm_start,vma->vm_end);
+       map->count++;
+}
+
+static void
+videobuf_vm_close(struct vm_area_struct *vma)
+{
+       struct videobuf_mapping *map = vma->vm_private_data;
+       struct videobuf_queue *q = map->q;
+       struct videbuf_pci_sg_memory *mem;
+       int i;
+
+       dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map,
+               map->count,vma->vm_start,vma->vm_end);
+
+       map->count--;
+       if (0 == map->count) {
+               dprintk(1,"munmap %p q=%p\n",map,q);
+               mutex_lock(&q->lock);
+               for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+                       if (NULL == q->bufs[i])
+                               continue;
+                       mem=q->bufs[i]->priv;
+
+                       if (!mem)
+                               continue;
+
+                       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+                       if (mem->map != map)
+                               continue;
+                       mem->map   = NULL;
+                       q->bufs[i]->baddr = 0;
+                       q->ops->buf_release(q,q->bufs[i]);
+               }
+               mutex_unlock(&q->lock);
+               kfree(map);
+       }
+       return;
+}
+
+/*
+ * Get a anonymous page for the mapping.  Make sure we can DMA to that
+ * memory location with 32bit PCI devices (i.e. don't use highmem for
+ * now ...).  Bounce buffers don't work very well for the data rates
+ * video capture has.
+ */
+static struct page*
+videobuf_vm_nopage(struct vm_area_struct *vma, unsigned long vaddr,
+                  int *type)
+{
+       struct page *page;
+
+       dprintk(3,"nopage: fault @ %08lx [vma %08lx-%08lx]\n",
+               vaddr,vma->vm_start,vma->vm_end);
+       if (vaddr > vma->vm_end)
+               return NOPAGE_SIGBUS;
+       page = alloc_page(GFP_USER | __GFP_DMA32);
+       if (!page)
+               return NOPAGE_OOM;
+       clear_user_page(page_address(page), vaddr, page);
+       if (type)
+               *type = VM_FAULT_MINOR;
+       return page;
+}
+
+static struct vm_operations_struct videobuf_vm_ops =
+{
+       .open     = videobuf_vm_open,
+       .close    = videobuf_vm_close,
+       .nopage   = videobuf_vm_nopage,
+};
+
+/* ---------------------------------------------------------------------
+ * PCI handlers for the generic methods
+ */
+
+/* Allocated area consists on 3 parts:
+       struct video_buffer
+       struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
+       struct videobuf_pci_sg_memory
+ */
+
+static void *__videobuf_alloc(size_t size)
+{
+       struct videbuf_pci_sg_memory *mem;
+       struct videobuf_buffer *vb;
+
+       vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
+
+       mem = vb->priv = ((char *)vb)+size;
+       mem->magic=MAGIC_SG_MEM;
+
+       videobuf_dma_init(&mem->dma);
+
+       dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
+               __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
+               mem,(long)sizeof(*mem));
+
+       return vb;
+}
+
+static int __videobuf_iolock (struct videobuf_queue* q,
+                             struct videobuf_buffer *vb,
+                             struct v4l2_framebuffer *fbuf)
+{
+       int err,pages;
+       dma_addr_t bus;
+       struct videbuf_pci_sg_memory *mem=vb->priv;
+       BUG_ON(!mem);
+
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       switch (vb->memory) {
+       case V4L2_MEMORY_MMAP:
+       case V4L2_MEMORY_USERPTR:
+               if (0 == vb->baddr) {
+                       /* no userspace addr -- kernel bounce buffer */
+                       pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
+                       err = videobuf_dma_init_kernel( &mem->dma,
+                                                       PCI_DMA_FROMDEVICE,
+                                                       pages );
+                       if (0 != err)
+                               return err;
+               } else {
+                       /* dma directly to userspace */
+                       err = videobuf_dma_init_user( &mem->dma,
+                                                     PCI_DMA_FROMDEVICE,
+                                                     vb->baddr,vb->bsize );
+                       if (0 != err)
+                               return err;
+               }
+               break;
+       case V4L2_MEMORY_OVERLAY:
+               if (NULL == fbuf)
+                       return -EINVAL;
+               /* FIXME: need sanity checks for vb->boff */
+               /*
+                * Using a double cast to avoid compiler warnings when
+                * building for PAE. Compiler doesn't like direct casting
+                * of a 32 bit ptr to 64 bit integer.
+                */
+               bus   = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
+               pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
+               err = videobuf_dma_init_overlay(&mem->dma,PCI_DMA_FROMDEVICE,
+                                               bus, pages);
+               if (0 != err)
+                       return err;
+               break;
+       default:
+               BUG();
+       }
+       err = videobuf_dma_map(q,&mem->dma);
+       if (0 != err)
+               return err;
+
+       return 0;
+}
+
+static int __videobuf_sync(struct videobuf_queue *q,
+                          struct videobuf_buffer *buf)
+{
+       struct videbuf_pci_sg_memory *mem=buf->priv;
+       BUG_ON (!mem);
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       return  videobuf_dma_sync(q,&mem->dma);
+}
+
+static int __videobuf_mmap_free(struct videobuf_queue *q)
+{
+       int i;
+
+       for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+               if (q->bufs[i]) {
+                       struct videbuf_pci_sg_memory *mem=q->bufs[i]->priv;
+                       if (mem && mem->map)
+                               return -EBUSY;
+               }
+       }
+
+       return 0;
+}
+
+static int __videobuf_mmap_mapper(struct videobuf_queue *q,
+                        struct vm_area_struct *vma)
+{
+       struct videbuf_pci_sg_memory *mem;
+       struct videobuf_mapping *map;
+       unsigned int first,last,size,i;
+       int retval;
+
+       retval = -EINVAL;
+       if (!(vma->vm_flags & VM_WRITE)) {
+               dprintk(1,"mmap app bug: PROT_WRITE please\n");
+               goto done;
+       }
+       if (!(vma->vm_flags & VM_SHARED)) {
+               dprintk(1,"mmap app bug: MAP_SHARED please\n");
+               goto done;
+       }
+
+       /* look for first buffer to map */
+       for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+               if (NULL == q->bufs[first])
+                       continue;
+               mem=q->bufs[first]->priv;
+               BUG_ON (!mem);
+               MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+               if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
+                       continue;
+               if (q->bufs[first]->boff == (vma->vm_pgoff << PAGE_SHIFT))
+                       break;
+       }
+       if (VIDEO_MAX_FRAME == first) {
+               dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
+                       (vma->vm_pgoff << PAGE_SHIFT));
+               goto done;
+       }
+
+       /* look for last buffer to map */
+       for (size = 0, last = first; last < VIDEO_MAX_FRAME; last++) {
+               if (NULL == q->bufs[last])
+                       continue;
+               if (V4L2_MEMORY_MMAP != q->bufs[last]->memory)
+                       continue;
+               mem=q->bufs[last]->priv;
+               if (mem->map) {
+                       retval = -EBUSY;
+                       goto done;
+               }
+               size += q->bufs[last]->bsize;
+               if (size == (vma->vm_end - vma->vm_start))
+                       break;
+       }
+       if (VIDEO_MAX_FRAME == last) {
+               dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
+                       (vma->vm_end - vma->vm_start));
+               goto done;
+       }
+
+       /* create mapping + update buffer list */
+       retval = -ENOMEM;
+       map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
+       if (NULL == map)
+               goto done;
+       for (size = 0, i = first; i <= last; size += q->bufs[i++]->bsize) {
+               mem=q->bufs[i]->priv;
+               mem->map   = map;
+               q->bufs[i]->baddr = vma->vm_start + size;
+       }
+       map->count    = 1;
+       map->start    = vma->vm_start;
+       map->end      = vma->vm_end;
+       map->q        = q;
+       vma->vm_ops   = &videobuf_vm_ops;
+       vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
+       vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
+       vma->vm_private_data = map;
+       dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
+               map,q,vma->vm_start,vma->vm_end,vma->vm_pgoff,first,last);
+       retval = 0;
+
+ done:
+       return retval;
+}
+
+static int __videobuf_is_mmapped (struct videobuf_buffer *buf)
+{
+       struct videbuf_pci_sg_memory *mem=buf->priv;
+
+       BUG_ON (!mem);
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       return (mem->map)?1:0;
+}
+
+static int __videobuf_copy_to_user ( struct videobuf_queue *q,
+                               char __user *data, size_t count,
+                               int nonblocking )
+{
+       struct videbuf_pci_sg_memory *mem=q->read_buf->priv;
+       BUG_ON (!mem);
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       /* copy to userspace */
+       if (count > q->read_buf->size - q->read_off)
+               count = q->read_buf->size - q->read_off;
+
+       if (copy_to_user(data, mem->dma.vmalloc+q->read_off, count))
+               return -EFAULT;
+
+       return count;
+}
+
+static int __videobuf_copy_stream ( struct videobuf_queue *q,
+                               char __user *data, size_t count, size_t pos,
+                               int vbihack, int nonblocking )
+{
+       unsigned int  *fc;
+       struct videbuf_pci_sg_memory *mem=q->read_buf->priv;
+       BUG_ON (!mem);
+       MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
+
+       if (vbihack) {
+               /* dirty, undocumented hack -- pass the frame counter
+                       * within the last four bytes of each vbi data block.
+                       * We need that one to maintain backward compatibility
+                       * to all vbi decoding software out there ... */
+               fc  = (unsigned int*)mem->dma.vmalloc;
+               fc += (q->read_buf->size>>2) -1;
+               *fc = q->read_buf->field_count >> 1;
+               dprintk(1,"vbihack: %d\n",*fc);
+       }
+
+       /* copy stuff using the common method */
+       count = __videobuf_copy_to_user (q,data,count,nonblocking);
+
+       if ( (count==-EFAULT) && (0 == pos) )
+               return -EFAULT;
+
+       return count;
+}
+
+static struct videobuf_qtype_ops pci_ops = {
+       .magic        = MAGIC_QTYPE_OPS,
+
+       .alloc        = __videobuf_alloc,
+       .iolock       = __videobuf_iolock,
+       .sync         = __videobuf_sync,
+       .mmap_free    = __videobuf_mmap_free,
+       .mmap_mapper  = __videobuf_mmap_mapper,
+       .is_mmapped   = __videobuf_is_mmapped,
+       .copy_to_user = __videobuf_copy_to_user,
+       .copy_stream  = __videobuf_copy_stream,
+};
+
+void *videobuf_pci_alloc (size_t size)
+{
+       struct videobuf_queue q;
+
+       /* Required to make generic handler to call __videobuf_alloc */
+       q.int_ops=&pci_ops;
+
+       q.msize=size;
+
+       return videobuf_alloc (&q);
+}
+
+void videobuf_queue_pci_init(struct videobuf_queue* q,
+                        struct videobuf_queue_ops *ops,
+                        void *dev,
+                        spinlock_t *irqlock,
+                        enum v4l2_buf_type type,
+                        enum v4l2_field field,
+                        unsigned int msize,
+                        void *priv)
+{
+       struct videobuf_dma_sg_ops *priv_ops;
+
+       videobuf_queue_init(q, ops, dev, irqlock, type, field, msize, priv);
+       q->int_ops=&pci_ops;
+
+       /* FIXME: the code bellow should be removed after having a proper
+        * memory allocation method for vivi and tm6000
+        */
+       q->priv_ops= kzalloc(sizeof(struct videobuf_dma_sg_ops), GFP_KERNEL);
+       BUG_ON (!q->priv_ops);
+
+       priv_ops=q->priv_ops;
+
+       /* Sets default methods for handling Scatter Gather mapping */
+       priv_ops->vb_map_sg=(vb_map_sg_t *)pci_map_sg;
+       priv_ops->vb_unmap_sg=(vb_map_sg_t *)pci_unmap_sg;
+       priv_ops->vb_dma_sync_sg=(vb_map_sg_t *)pci_dma_sync_sg_for_cpu;
+}
+
+void videobuf_set_pci_ops (struct videobuf_queue* q,
+                               struct videobuf_dma_sg_ops *ops)
+{
+       kfree (q->priv_ops);
+
+       q->priv_ops=ops;
+
+       if (!ops)
+               return;
+
+       /* If not specified, defaults to PCI map sg */
+       if (!ops->vb_map_sg)
+               ops->vb_map_sg=(vb_map_sg_t *)pci_map_sg;
+
+       if (!ops->vb_dma_sync_sg)
+               ops->vb_dma_sync_sg=(vb_map_sg_t *)pci_dma_sync_sg_for_cpu;
+       if (!ops->vb_unmap_sg)
+               ops->vb_unmap_sg=(vb_map_sg_t *)pci_unmap_sg;
+}
+
+
+/* --------------------------------------------------------------------- */
+
+EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg);
+
+EXPORT_SYMBOL_GPL(videobuf_to_dma);
+EXPORT_SYMBOL_GPL(videobuf_dma_init);
+EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
+EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
+EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
+EXPORT_SYMBOL_GPL(videobuf_dma_map);
+EXPORT_SYMBOL_GPL(videobuf_dma_sync);
+EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
+EXPORT_SYMBOL_GPL(videobuf_dma_free);
+
+EXPORT_SYMBOL_GPL(videobuf_pci_dma_map);
+EXPORT_SYMBOL_GPL(videobuf_pci_dma_unmap);
+EXPORT_SYMBOL_GPL(videobuf_pci_alloc);
+
+EXPORT_SYMBOL_GPL(videobuf_queue_pci_init);
+EXPORT_SYMBOL_GPL(videobuf_set_pci_ops);
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */
diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h
new file mode 100644
index 0000000..0ac21ae
--- /dev/null
+++ b/include/media/videobuf-core.h
@@ -0,0 +1,236 @@
+/*
+ * generic helper functions for handling video4linux capture buffers
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <[EMAIL PROTECTED]>
+ * (c) 2006 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2
+ */
+
+#include <linux/poll.h>
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+#include <linux/videodev.h>
+#endif
+#include <linux/videodev2.h>
+
+#define UNSET (-1U)
+
+
+struct videobuf_buffer;
+struct videobuf_queue;
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * A small set of helper functions to manage video4linux buffers.
+ *
+ * struct videobuf_buffer holds the data structures used by the helper
+ * functions, additionally some commonly used fields for v4l buffers
+ * (width, height, lists, waitqueue) are in there.  That struct should
+ * be used as first element in the drivers buffer struct.
+ *
+ * about the mmap helpers (videobuf_mmap_*):
+ *
+ * The mmaper function allows to map any subset of contingous buffers.
+ * This includes one mmap() call for all buffers (which the original
+ * video4linux API uses) as well as one mmap() for every single buffer
+ * (which v4l2 uses).
+ *
+ * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
+ * userspace address + size which can be feeded into the
+ * videobuf_dma_init_user function listed above.
+ *
+ */
+
+struct videobuf_mapping {
+       unsigned int count;
+       unsigned long start;
+       unsigned long end;
+       struct videobuf_queue *q;
+};
+
+enum videobuf_state {
+       STATE_NEEDS_INIT = 0,
+       STATE_PREPARED   = 1,
+       STATE_QUEUED     = 2,
+       STATE_ACTIVE     = 3,
+       STATE_DONE       = 4,
+       STATE_ERROR      = 5,
+       STATE_IDLE       = 6,
+};
+
+struct videobuf_buffer {
+       unsigned int            i;
+       u32                     magic;
+
+       /* info about the buffer */
+       unsigned int            width;
+       unsigned int            height;
+       unsigned int            bytesperline; /* use only if != 0 */
+       unsigned long           size;
+       unsigned int            input;
+       enum v4l2_field         field;
+       enum videobuf_state     state;
+       struct list_head        stream;  /* QBUF/DQBUF list */
+
+       /* touched by irq handler */
+       struct list_head        queue;
+       wait_queue_head_t       done;
+       unsigned int            field_count;
+       struct timeval          ts;
+
+       /* Memory type */
+       enum v4l2_memory        memory;
+
+       /* buffer size */
+       size_t                  bsize;
+
+       /* buffer offset (mmap + overlay) */
+       size_t                  boff;
+
+       /* buffer addr (userland ptr!) */
+       unsigned long           baddr;
+
+       /* Private pointer to allow specific methods to store their data */
+       int                     privsize;
+       void                    *priv;
+};
+
+struct videobuf_queue_ops {
+       int (*buf_setup)(struct videobuf_queue *q,
+                        unsigned int *count, unsigned int *size);
+       int (*buf_prepare)(struct videobuf_queue *q,
+                          struct videobuf_buffer *vb,
+                          enum v4l2_field field);
+       void (*buf_queue)(struct videobuf_queue *q,
+                         struct videobuf_buffer *vb);
+       void (*buf_release)(struct videobuf_queue *q,
+                           struct videobuf_buffer *vb);
+};
+
+#define MAGIC_QTYPE_OPS        0x12261003
+
+/* Helper operations - device type dependent */
+struct videobuf_qtype_ops {
+       u32                     magic;
+
+       void* (*alloc)          (size_t size);
+       int (*iolock)           (struct videobuf_queue* q,
+                                struct videobuf_buffer *vb,
+                                struct v4l2_framebuffer *fbuf);
+       int (*mmap)             (struct videobuf_queue *q,
+                                unsigned int *count,
+                                unsigned int *size,
+                                enum v4l2_memory memory);
+       int (*sync)             (struct videobuf_queue* q,
+                                struct videobuf_buffer *buf);
+       int (*copy_to_user)     (struct videobuf_queue *q,
+                                char __user *data,
+                                size_t count,
+                                int nonblocking);
+       int (*copy_stream)      (struct videobuf_queue *q,
+                                char __user *data,
+                                size_t count,
+                                size_t pos,
+                                int vbihack,
+                                int nonblocking);
+       int (*mmap_free)        (struct videobuf_queue *q);
+       int (*mmap_mapper)      (struct videobuf_queue *q,
+                               struct vm_area_struct *vma);
+       int (*is_mmapped)       (struct videobuf_buffer *buf);
+};
+
+struct videobuf_queue {
+       struct mutex               lock;
+       spinlock_t                 *irqlock;
+       void                       *dev; /* on pci, points to struct pci_dev */
+
+       enum v4l2_buf_type         type;
+       unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
+       unsigned int               msize;
+       enum v4l2_field            field;
+       enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
+       struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
+       struct videobuf_queue_ops  *ops;
+       struct videobuf_qtype_ops  *int_ops;
+
+       /* capture via mmap() + ioctl(QBUF/DQBUF) */
+       unsigned int               streaming;
+       struct list_head           stream;
+
+       /* capture via read() */
+       unsigned int               reading;
+       unsigned int               read_off;
+       struct videobuf_buffer     *read_buf;
+
+       /* driver private data */
+       void                       *priv_data;
+
+       /*FIXME: should be removed after completing the vb conversion */
+       void                       *priv_ops;
+};
+
+int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
+int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
+               struct v4l2_framebuffer *fbuf);
+
+void *videobuf_alloc(struct videobuf_queue* q);
+
+void videobuf_queue_init(struct videobuf_queue *q,
+                        struct videobuf_queue_ops *ops,
+                        void *dev,
+                        spinlock_t *irqlock,
+                        enum v4l2_buf_type type,
+                        enum v4l2_field field,
+                        unsigned int msize,
+                        void *priv);
+int  videobuf_queue_is_busy(struct videobuf_queue *q);
+void videobuf_queue_cancel(struct videobuf_queue *q);
+
+enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
+int videobuf_reqbufs(struct videobuf_queue *q,
+                    struct v4l2_requestbuffers *req);
+int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
+int videobuf_qbuf(struct videobuf_queue *q,
+                 struct v4l2_buffer *b);
+int videobuf_dqbuf(struct videobuf_queue *q,
+                  struct v4l2_buffer *b, int nonblocking);
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+int videobuf_cgmbuf(struct videobuf_queue *q,
+                   struct video_mbuf *mbuf, int count);
+#endif
+int videobuf_streamon(struct videobuf_queue *q);
+int videobuf_streamoff(struct videobuf_queue *q);
+
+int videobuf_read_start(struct videobuf_queue *q);
+void videobuf_read_stop(struct videobuf_queue *q);
+ssize_t videobuf_read_stream(struct videobuf_queue *q,
+                            char __user *data, size_t count, loff_t *ppos,
+                            int vbihack, int nonblocking);
+ssize_t videobuf_read_one(struct videobuf_queue *q,
+                         char __user *data, size_t count, loff_t *ppos,
+                         int nonblocking);
+unsigned int videobuf_poll_stream(struct file *file,
+                                 struct videobuf_queue *q,
+                                 poll_table *wait);
+
+int videobuf_mmap_setup(struct videobuf_queue *q,
+                       unsigned int bcount, unsigned int bsize,
+                       enum v4l2_memory memory);
+int videobuf_mmap_free(struct videobuf_queue *q);
+int videobuf_mmap_mapper(struct videobuf_queue *q,
+                        struct vm_area_struct *vma);
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */
diff --git a/include/media/videobuf-dma-sg.h b/include/media/videobuf-dma-sg.h
new file mode 100644
index 0000000..62a3709
--- /dev/null
+++ b/include/media/videobuf-dma-sg.h
@@ -0,0 +1,142 @@
+/*
+ * helper functions for PCI DMA video4linux capture buffers
+ *
+ * The functions expect the hardware being able to scatter gatter
+ * (i.e. the buffers are not linear in physical memory, but fragmented
+ * into PAGE_SIZE chunks).  They also assume the driver does not need
+ * to touch the video data.
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <[EMAIL PROTECTED]>
+ * (c) 2006 Mauro Carvalho Chehab, <[EMAIL PROTECTED]>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2
+ */
+
+#include <media/videobuf-core.h>
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * Return a scatterlist for some page-aligned vmalloc()'ed memory
+ * block (NULL on errors).  Memory for the scatterlist is allocated
+ * using kmalloc.  The caller must free the memory.
+ */
+struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
+
+/*
+ * Return a scatterlist for a an array of userpages (NULL on errors).
+ * Memory for the scatterlist is allocated using kmalloc.  The caller
+ * must free the memory.
+ */
+struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
+                                        int offset);
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * A small set of helper functions to manage buffers (both userland
+ * and kernel) for DMA.
+ *
+ * videobuf_dma_init_*()
+ *     creates a buffer.  The userland version takes a userspace
+ *     pointer + length.  The kernel version just wants the size and
+ *     does memory allocation too using vmalloc_32().
+ *
+ * videobuf_dma_*()
+ *     see Documentation/DMA-mapping.txt, these functions to
+ *     basically the same.  The map function does also build a
+ *     scatterlist for the buffer (and unmap frees it ...)
+ *
+ * videobuf_dma_free()
+ *     no comment ...
+ *
+ */
+
+struct videobuf_dmabuf {
+       u32                 magic;
+
+       /* for userland buffer */
+       int                 offset;
+       struct page         **pages;
+
+       /* for kernel buffers */
+       void                *vmalloc;
+
+       /* Stores the userspace pointer to vmalloc area */
+       void                *varea;
+
+       /* for overlay buffers (pci-pci dma) */
+       dma_addr_t          bus_addr;
+
+       /* common */
+       struct scatterlist  *sglist;
+       int                 sglen;
+       int                 nr_pages;
+       int                 direction;
+};
+
+struct videbuf_pci_sg_memory
+{
+       u32                 magic;
+
+       /* for mmap'ed buffers */
+       struct videobuf_mapping *map;
+       struct videobuf_dmabuf  dma;
+};
+
+/* FIXME: To be removed soon */
+typedef int (vb_map_sg_t)(void *dev, struct scatterlist *sglist, int nr_pages,
+                                       int direction);
+
+/* FIXME: To be removed soon */
+struct videobuf_dma_sg_ops
+{
+       vb_map_sg_t     *vb_map_sg;
+       vb_map_sg_t     *vb_dma_sync_sg;
+       vb_map_sg_t     *vb_unmap_sg;
+
+};
+
+void videobuf_dma_init(struct videobuf_dmabuf *dma);
+int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
+                          unsigned long data, unsigned long size);
+int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
+                            int nr_pages);
+int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
+                             dma_addr_t addr, int nr_pages);
+int videobuf_dma_free(struct videobuf_dmabuf *dma);
+
+int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
+int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
+int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
+struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf);
+
+void *videobuf_pci_alloc (size_t size);
+
+void videobuf_queue_pci_init(struct videobuf_queue* q,
+                        struct videobuf_queue_ops *ops,
+                        void *dev,
+                        spinlock_t *irqlock,
+                        enum v4l2_buf_type type,
+                        enum v4l2_field field,
+                        unsigned int msize,
+                        void *priv);
+
+       /*FIXME: these variants are used only on *-alsa code, where videobuf is
+        * used without queue
+        */
+int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma);
+int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma);
+
+/* FIXME: temporary routine for vivi and tm6000, while lacking implementation
+ * of videobuf-vmalloc
+ */
+void videobuf_set_pci_ops (struct videobuf_queue* q,
+                               struct videobuf_dma_sg_ops *ops);
+
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